Don't a bunch of squids, birds, other primates, etc. show plenty of intelligence? Yet none show any ambition to develop high tech that anyone could spot from space, chimps don't even feel the need to communicate all that much even though they're totally capable of using sign language when properly incentivized, they just don't seem to have the urge to express themselves like we do.
Might that not imply that intelligence is pretty frequent, but that what we're looking for isn't intelligence per se, but a bunch of other very specific qualities and factors that channel intelligence to express itself in high tech spacefaring ways? Seeing how much had to fall into place just so in the last 100 000 years so we could put someone on the moon, I guess that seems plausible?
That’s mostly a question of how one chooses to define “intelligence.” For the purposes of this type of discussion it’s usually equivalent to “whatever humans have that other animals don’t.” We’re looking for something that would be relatable to us, probably the minimum requirement would be the ability to communicate with them at the same level of robustness that we can with each other (edit: or a recognizable demonstration of mastery over the physical world to a level that meets or exceeds our own).
It’s true that other terrestrial life forms possess some capabilities that we could call intelligence, but then we would just need to use another word that defines the special human je ne sais quoi.
Probably the most relevant difference is humans forming prestige hierarchies alongside dominance hierarchies with larger brains able to store more of the resulting cultural accumulation being partially downstream of that. Knowledge transmission is always imperfect but if people try to learn from the guy reputed to be the best flint napper you can support a lot more technology than if everybody just learns from their parents.
Learning from non-kin isn't unusual in the animal kingdom. Monkeys seeing other monkeys drop a mix of sand and grain in water to separate them and then copying that is a classic example. But deliberate teaching of non-kin and the way we use language to help with that teaching is pretty unique. An octopus might have smarts comparable to a feral human, but not to an acculturated human.
Yet none show any ambition to develop high tech that anyone could spot from space
Above the sea level, anyone who had it is either a part of “our” genome or extinct. Below it is a completely separate biome which may not yet had an event starting this type of evolution. It’s unclear if in a million years (in the absence of humans) squids would stay the same or evolve into walking and then moon-landing.
I think that only one species can do that, because the most energetic natural environment (free oxygen in our case), which is required for it, is usually only one per planet, and you have to fight over it, with hands, wood, metals, fire, ATGMs.
I mean one can spot an elephant from space, but a crow? :) I was talking in a high-tech context, of course there are pretty intelligent species besides us, but they don’t build lit up megastructures.
The comment you were responding to already has that as an assumption and is saying that they don't do those things not because they can't but because they don't have ambition to do them, so the fact that they don't isn't a measure of intelligence.
You can see beaver dams from space, or atmospheric oxygen. Only sending radio signals is uniquely human.
In terms of space, single called organisms have traveled further from earth than people have. So calling us spacefaring is kind of misleading in the context of alien life. I doubt we’re detectable outside of a 100 light year sphere from earth and none of those stars look like they contain any habitable planets. The only way to suggest alien intelligent life is meaningfully different than beavers in this context is to raise the bar far enough we don’t qualify.
You can build better receivers but eventually only so many photons are being sent. Prior to 1921 people were sending out very little radio waves and the signals where vary weak. The you might move things back to say 1920 with the very first radio station but it really wasn’t putting out much power. Things ramped up fairly quickly though, at least assuming something built a truly massive detector at 100+light years.
For comparison look at what we need to do to detect messages from the voyager 1 at 1/400th a light year, realize that’s sent from a directional antenna and we know exactly where to look for it. A signal that’s ~1/1,600,000,000th as strong would take some serious hardware even with more advanced technology because you can only collect 100% of the photons in a radio transmission quickly you need a physically larger device.
GP's reasoning is probably: the only plausible way to detect human civilization (and not just our planet, which is already hard enough from a different star) is by it's radio signature, and the oldest radio emissions is from 100 years ago, give or take. Anyone standing outside of a sphere whose center is earth and radius is 100 light year hadn't been reached by our oldest detectable-from-space civilization artifacts yet.
It strikes me as a pretty intuitive arguemnt to make and true by default, to show it wrong you have to find or somehow plausibly argue for the existence of some physical medium or process that human civilization (or even earth life in general) emit or modulate in unique, detectable-from-space ways other than electromagnetic waves and that we have been doing this since before radio.
I think it might be considered evidence, but CO2 levels vary quite a bit over time. Picture what would happen if we measured atmospheric bass on a planet over a few hundred years and saw that kind of swing in CO2.
Decidable radio signals on the other hand are far less ambiguous. I just can’t think of much that would be both detectable and a smoking gun.
In general, the signal from our most powerful commercial radio transmitters will go below the background noise floor well before 100 light years.
However, a very low bandwidth pumped through something on the scale of the Arecibo dish at the transmitting end, and a helium-cooled receiver, could bridge many more light years. But then we're no longer talking about a sphere of a signal or even a big cone, but in astronomical terms an extremely tight-focused point-to-point laser that is more apt to just intersect cosmic dust and gases than an alien civilization.
> However if the aliens had a big telescope surely that radius would expand?
I think a more interesting question is how far away could we detect a civilisation equivalent to our own, using our current technology. Otherwise you can assume aliens (or our future selves) with arbitrarily sensitive detection equipment limited only by whether or not the detectors are inside the speed-of-light radius of the emitting civilisation.
IIRC our most powerful transmissions have been from NORAD radars looking for missiles coming over the north pole. In some ways we are now emitting less detectable signals, e.g. with lower power 5G cells and fibre broadband replacing good old radio.
There is clear line between human and animal intelligence, the language. It's this ability to exchange information about arbitrarily complex ideas, or, one might say, to exchange and store thoughts in a serialized form, that sets our intelligence apart and opens the possibilities for a civilization as advanced as ours. No other species on this planet has I/O capabilities this advanced.
Indeed, I think it's clear a lot of animals can do a lot of things that they just don't want to do and the reason they don't want to is because that just wasn't beneficial for them in their environment. Maybe cultures could be created and spread amongst them that might bring out that ambition though.
> chimps don't even feel the need to communicate all that much
Because that wasn't providing any evolutionary benefit. Take a group of chimps, and make offspring of those who communicate more often to have a higher chance of survival, and voila -- they will develop an urge to communicate!
Humans also didn't show any ambition, besides keeping themselves and their little band alive, for hundreds of thousands of years. We know they had the mental capacity because hunting, foraging, cooking and tool-making needs knowledge and planning, but they were fine as they were.
Somehow humans started cooperating in large groups, planting the seeds of civilization, outcompeting (or possibly exterminating) our less social brethren. We can't know if the first human capable of leading large groups was a genius or a psychopath, but without people like him/her humanity probably wouldn't be very ambitious.
Might that not imply that intelligence is pretty frequent, but that what we're looking for isn't intelligence per se, but a bunch of other very specific qualities and factors that channel intelligence to express itself in high tech spacefaring ways? Seeing how much had to fall into place just so in the last 100 000 years so we could put someone on the moon, I guess that seems plausible?